812138 - BaselineCompiler: Implement numFrameSlots/frameSlotValue for baseline frames

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

Attachment: Patch

These are only used by the expression decompiler stack search. There may be fewer or more values on the stack, but that's handled correctly by the decompiler. And IonMonkey has the same problem (the snapshot it uses encodes the state at another pc).

Comment 1

[Kannan Vijayan [:djvj]]

Comment on attachment 681942 [details] [diff] [review]
Patch

Review of attachment 681942 [details] [diff] [review]:
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::: js/src/vm/Stack.cpp
@@ +1785,5 @@
>        case ION:
>  #ifdef JS_ION
> +        if (ionFrames_.isOptimizedJS())
> +            return ionInlineFrames_.snapshotIterator().slots() - ionInlineFrames_.script()->nfixed;
> +        return ionFrames_.numBaselineStackValues() - ionFrames_.script()->nfixed;

This would be clearer as an if-else instead of a terminating if with a fallthrough.

@@ +1815,5 @@
> +            return si.maybeReadSlotByIndex(index);
> +        }
> +
> +        index += ionFrames_.script()->nfixed;
> +        return ionFrames_.baselineStackValue(index);

Same as above.  The logic here is choosing two different actions based on isOptimizedJS(), not shortcutting a larger action based on isOptimizedJS().

Comment 2

[Jan de Mooij [:jandem]]

SM has a "no else after return" style rule.

https://hg.mozilla.org/projects/ionmonkey/rev/5d220bff87f0